The oldest record of gnathostome fossils from Greece: Chondrichthyes from the Lopingian of Hydra Island

Until now, no jawed vertebrate (fishes and tetrapods) fossils were known from Paleozoic deposits in Greece. Recent fieldwork on Hydra Island, Western Aegean Sea, brought to light some 255 million year old shark remains. Tooth anatomy suggests that the Hydriot shark fed on hard, likely shelled prey, and shows anatomical similarities with other iconic Paleozoic and Mesozoic bottom feeding sharks. However, fine anatomical differences, like tooth ornamentation, do not allow us to include the Hydriot shark in any previously known species. The Hydriot shark material is not only the first known occurrence of jawed vertebrates in Greece, but also corresponds to one of the few occurrences of such animals in the late Paleozoic sediments of the Paleotethyan Ocean.